petere
2b3fd54934
- config: validate port/quality/fps/source/stream-index ranges on load and before engine start (flinger.Config.Validate) - discovery: add Announce option to disable multicast (GUI checkbox, CLI --no-announce); absent JSON key keeps the default true - backpressure: count dropped frames in the TCP sender, expose via engine Status and a live counter in the GUI status label - docs: record M3/M4 decisions and X11 coverage via the portal backend
460 lines
11 KiB
Go
460 lines
11 KiB
Go
// Package flinger implements the TeleportFling streaming engine: it captures
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// a screen (and optionally system audio), encodes video to JPEG, packetizes
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// both into the Teleport protocol, and broadcasts them to connected OBS
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// receivers.
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//
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// The engine is deliberately GUI-free so it can run headless (CLI/daemon) or
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// be driven by a desktop app. Callers create an Engine with a Config, call
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// Start, poll Status, and call Stop when done.
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package flinger
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import (
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"errors"
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"image"
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"image/color"
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"io"
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"log"
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"strconv"
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"sync/atomic"
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"time"
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"teleportfling/internal/capture"
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"teleportfling/internal/discovery"
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"teleportfling/internal/output"
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"teleportfling/internal/protocol"
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)
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const (
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// sampleRate and speakers describe the captured/encoded audio stream.
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sampleRate = 48000
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speakers = 2
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// audioChunk sets how much audio we packetize per WAVE message (~10 ms).
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audioChunk = 10 * time.Millisecond
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)
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// Config configures the streaming engine.
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type Config struct {
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// Name is the announce name advertised to receivers (empty → hostname).
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Name string
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// Port is the TCP listening port for receivers.
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Port int
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// Quality is the JPEG quality, 1–100.
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Quality int
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// FPS is the target video frame rate.
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FPS int
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// Source is "screen" (PipeWire) or "pattern" (synthetic test signal).
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Source string
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// Audio enables system audio capture and streaming.
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Audio bool
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// StreamIndex selects which monitor to capture (screen source only).
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StreamIndex int
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// Announce controls whether the stream is advertised via UDP multicast.
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// When disabled, receivers must connect by IP manually.
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Announce bool
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}
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// DefaultConfig returns the recommended defaults.
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func DefaultConfig() Config {
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return Config{
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Port: 9756,
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Quality: 80,
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FPS: 30,
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Source: "screen",
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Audio: true,
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Announce: true,
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}
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}
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// Validate checks the config for out-of-range or unsupported values.
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func (c Config) Validate() error {
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if c.Port < 1 || c.Port > 65535 {
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return errors.New("port must be 1–65535")
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}
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if c.Quality < 1 || c.Quality > 100 {
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return errors.New("quality must be 1–100")
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}
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if c.FPS < 1 || c.FPS > 240 {
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return errors.New("fps must be 1–240")
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}
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if c.Source != "screen" && c.Source != "pattern" {
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return errors.New("source must be screen or pattern")
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}
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if c.StreamIndex < 0 {
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return errors.New("stream index must be >= 0")
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}
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return nil
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}
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// Status is a point-in-time snapshot of the running engine.
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type Status struct {
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Running bool
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Frames int64
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Dropped int64
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Conns int
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}
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// Engine owns the capture, encode and send pipeline.
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type Engine struct {
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cfg Config
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sender *output.Sender
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announcer *discovery.Announcer
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encoder *protocol.JPEGEncoder
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cam capture.Capture
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loop frameSource
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start time.Time
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stop chan struct{}
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frames atomic.Int64
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}
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// New creates an engine from cfg. Capture is opened eagerly so that
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// misconfiguration (e.g. no screen-share permission) surfaces before Start.
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func New(cfg Config) (*Engine, error) {
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if err := cfg.Validate(); err != nil {
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return nil, err
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}
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e := &Engine{cfg: cfg}
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sender := output.New()
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if _, err := sender.Listen(addr(cfg.Port)); err != nil {
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return nil, err
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}
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enc, err := protocol.NewJPEGEncoder()
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if err != nil {
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sender.Close()
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return nil, err
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}
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e.sender = sender
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e.encoder = enc
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switch cfg.Source {
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case "screen":
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cam, err := capture.OpenPipeWire(cfg.StreamIndex, cfg.Audio)
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if err != nil {
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e.encoder.Close()
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sender.Close()
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return nil, err
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}
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e.cam = cam
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e.loop = captureLoop{cam}
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case "pattern":
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e.loop = &patternLoop{w: 1920, h: 1080}
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default:
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e.encoder.Close()
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sender.Close()
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return nil, errors.New("unknown source " + cfg.Source)
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}
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return e, nil
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}
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// Start begins the audio, video and stats loops and (unless disabled in the
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// config) starts announcing the stream. It is idempotent.
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func (e *Engine) Start() {
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if e.stop != nil {
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return
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}
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e.start = time.Now()
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e.stop = make(chan struct{})
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if e.cfg.Announce {
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e.announcer = discovery.Start(e.cfg.Name, e.sender.Port())
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}
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var src io.ReadCloser
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switch {
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case e.cam == nil:
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src = capture.NewSilenceSource()
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case e.cam.Audio() != nil:
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src = e.cam.Audio()
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default:
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log.Printf("flinger: system audio unavailable, streaming silence")
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src = capture.NewSilenceSource()
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}
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go e.audioLoop(src)
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go e.videoLoop()
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go e.statsLoop()
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}
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// Stop halts the loops, stops announcing and closes all resources. It is
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// idempotent. After Stop the engine must not be restarted.
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func (e *Engine) Stop() {
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if e.stop == nil {
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return
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}
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close(e.stop)
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// Give the loops a moment to observe the stop signal.
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time.Sleep(50 * time.Millisecond)
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if e.announcer != nil {
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e.announcer.Stop()
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}
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e.sender.Close()
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e.encoder.Close()
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if e.cam != nil {
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if err := e.cam.Close(); err != nil {
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log.Printf("flinger: capture close: %v", err)
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}
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}
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}
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// Status returns a snapshot of the running engine.
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func (e *Engine) Status() Status {
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return Status{
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Running: e.stop != nil,
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Frames: e.frames.Load(),
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Dropped: e.sender.Dropped(),
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Conns: e.sender.NumConns(),
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}
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}
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// audioLoop reads raw PCM and emits WAVE packets. start is the shared
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// reference clock used by the video loop so audio and video timestamps stay
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// aligned on the receiver.
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func (e *Engine) audioLoop(src io.ReadCloser) {
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defer func() { _ = src.Close() }()
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framesPerChunk := int(sampleRate) * int(audioChunk) / int(time.Second)
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chunkBytes := framesPerChunk * speakers * 2 // S16
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buf := make([]byte, chunkBytes)
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for {
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n, err := io.ReadFull(src, buf)
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if n > 0 {
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frames := n / (speakers * 2)
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ts := uint64(time.Since(e.start))
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packet, perr := protocol.BuildWavePacket(ts, protocol.AudioFormatS16, sampleRate, speakers, int32(frames), buf[:n])
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if perr != nil {
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log.Printf("flinger: wave: %v", perr)
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} else {
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e.sender.Send(packet)
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}
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}
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if err != nil {
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select {
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case <-e.stop:
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return
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default:
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}
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if !errors.Is(err, io.EOF) && !errors.Is(err, io.ErrClosedPipe) {
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log.Printf("flinger: audio: %v", err)
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}
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}
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}
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}
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// videoLoop pulls frames and sends them at the configured fps.
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func (e *Engine) videoLoop() {
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frameInterval := time.Second / time.Duration(e.cfg.FPS)
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next := e.start
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for {
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frame, err := e.loop.Next()
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if err != nil {
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select {
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case <-e.stop:
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return
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default:
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}
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if !errors.Is(err, io.EOF) && !errors.Is(err, io.ErrClosedPipe) {
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log.Printf("flinger: capture: %v", err)
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}
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continue
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}
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// Drop frames when running ahead of the target fps to keep
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// timestamps monotonic (e.g. a 60 Hz monitor captured at 30 fps).
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now := time.Now()
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if now.Before(next) {
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continue
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}
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next = now.Add(frameInterval)
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ts := uint64(now.Sub(e.start))
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buf, err := e.encoder.EncodeBGRA(frame.Pix, frame.Width, frame.Height, e.cfg.Quality)
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if err != nil {
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log.Printf("flinger: jpeg: %v", err)
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continue
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}
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packet, err := protocol.WritePacket(
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protocol.Header{Type: protocol.VideoType, Timestamp: ts, Size: int32(len(buf))},
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ptr(protocol.DefaultBT709Full()),
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nil,
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buf,
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)
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if err != nil {
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log.Printf("flinger: packet: %v", err)
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continue
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}
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e.sender.Send(packet)
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e.frames.Add(1)
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}
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}
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// statsLoop logs a periodic summary.
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func (e *Engine) statsLoop() {
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tick := time.NewTicker(5 * time.Second)
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defer tick.Stop()
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for {
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select {
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case <-tick.C:
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st := e.Status()
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if st.Dropped > 0 {
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log.Printf("flinger: %d frames, %d dropped, %d conns", st.Frames, st.Dropped, st.Conns)
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} else {
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log.Printf("flinger: %d frames, %d conns", st.Frames, st.Conns)
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}
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case <-e.stop:
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return
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}
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}
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}
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// frameSource abstracts the frame source: real capture or the test pattern.
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type frameSource interface {
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Next() (*capture.VideoFrame, error)
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}
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// captureLoop wraps the PipeWire capture backend.
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type captureLoop struct {
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cam capture.Capture
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}
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func (c captureLoop) Next() (*capture.VideoFrame, error) {
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return c.cam.Video().NextFrame()
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}
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// patternLoop synthesizes the M1 test pattern (colour bars + moving box).
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type patternLoop struct {
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w, h int
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seq int64
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}
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func (p *patternLoop) Next() (*capture.VideoFrame, error) {
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img := testPattern(p.w, p.h, int(p.seq))
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p.seq++
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return ycrcbToBGRA(img), nil
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}
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// ycrcbToBGRA converts a YCbCr image to a BGRA VideoFrame so both sources
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// share the encode path (EncodeBGRA).
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func ycrcbToBGRA(img *image.YCbCr) *capture.VideoFrame {
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w, h := img.Rect.Dx(), img.Rect.Dy()
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frame := &capture.VideoFrame{
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Pix: make([]byte, w*h*4),
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Width: w,
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Height: h,
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Stride: w * 4,
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}
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for y := 0; y < h; y++ {
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for x := 0; x < w; x++ {
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yi := y*img.YStride + x
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ci := (y/2)*img.CStride + x/2
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r, g, b := color.YCbCrToRGB(img.Y[yi], img.Cb[ci], img.Cr[ci])
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off := (y*w + x) * 4
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frame.Pix[off], frame.Pix[off+1], frame.Pix[off+2], frame.Pix[off+3] = b, g, r, 255
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}
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}
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return frame
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}
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// ptr returns a pointer to v, for passing headers to WritePacket.
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func ptr[T any](v T) *T { return &v }
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// addr formats a port as a listen address.
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func addr(port int) string {
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return ":" + strconv.Itoa(port)
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}
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// testPattern renders a standard SMPTE colour bar with a moving white box at
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// the given frame index.
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func testPattern(w, h, frame int) *image.YCbCr {
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img := image.NewYCbCr(image.Rect(0, 0, w, h), image.YCbCrSubsampleRatio420)
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// 7 vertical colour bars (grey, yellow, cyan, green, magenta, red, blue).
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bars := []color.RGBA{
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{R: 191, G: 191, B: 191}, // 75% grey
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{R: 191, G: 191, B: 0}, // yellow
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{R: 0, G: 191, B: 191}, // cyan
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{R: 0, G: 191, B: 0}, // green
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{R: 191, G: 0, B: 191}, // magenta
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{R: 191, G: 0, B: 0}, // red
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{R: 0, G: 0, B: 191}, // blue
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}
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const barCount = 7
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barW := w / barCount
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const boxSize = 80
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// Moving white box sweeps left→right across the lower black block.
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boxMinX := (frame*(w+boxSize)/120)%(w+boxSize) - boxSize/2
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buf := make([]color.RGBA, w*h)
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for by := 0; by < h; by++ {
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rowIsBars := by < h*2/3
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for bx := 0; bx < w; bx++ {
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var c color.RGBA
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switch {
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case rowIsBars:
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idx := bx / barW
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if idx >= barCount {
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idx = barCount - 1
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}
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c = bars[idx]
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case by%8 < 4 && bx > w/3 && bx < w*2/3:
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c = color.RGBA{R: 255, G: 255, B: 255, A: 255}
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default:
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c = color.RGBA{}
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}
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if bx >= boxMinX && bx < boxMinX+boxSize && by >= h*2/3 {
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c = color.RGBA{R: 255, G: 255, B: 255, A: 255}
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}
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buf[by*w+bx] = c
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}
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}
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// Chroma planes: average each 2x2 RGB block, then convert to Cb/Cr.
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for by := 0; by < h; by += 2 {
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for bx := 0; bx < w; bx += 2 {
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var rSum, gSum, bSum uint32
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n := uint32(0)
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for dy := 0; dy < 2; dy++ {
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for dx := 0; dx < 2; dx++ {
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xx, yy := bx+dx, by+dy
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if xx >= w || yy >= h {
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continue
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}
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px := buf[yy*w+xx]
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rSum += uint32(px.R)
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gSum += uint32(px.G)
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bSum += uint32(px.B)
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n++
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}
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}
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_, cb, cr := color.RGBToYCbCr(uint8(rSum/n), uint8(gSum/n), uint8(bSum/n))
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img.Cb[(by/2)*img.CStride+bx/2] = cb
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img.Cr[(by/2)*img.CStride+bx/2] = cr
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}
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}
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// Luma plane: Y = YCbCr luma of every pixel.
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for by := 0; by < h; by++ {
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for bx := 0; bx < w; bx++ {
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px := buf[by*w+bx]
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y, _, _ := color.RGBToYCbCr(px.R, px.G, px.B)
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img.Y[by*img.YStride+bx] = y
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}
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}
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return img
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}
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